Switching device



Jan. 17, 1950 R. E. MUMMA SWITCHING DEVICE 2 Sheets-Sheet 1 OriginalFiled Dec v 27, 1945 STAGE TY FIG. I

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STAGE III H3 STAGE I STAGE II 2260 IKIVENTOR ROBERT E. MUMMA HISATTORNEY.

m m 2 2 0 0 V O 9 8 0. O H V w 0 V 9 m V 8 O l 2 l O 2 H 0 H H l 7 7 7Jan. 17, 1950 R. E. MUMMA SWITCHING DEVICE 2 Sheets-Sheet 2 OriginalFiled Dec. 27, 1945 INVENTOR ROBERT MUMMA HIS ATTORNEY m- 1 Q2 (D4 BY MMPatented Jan. 17, 1950 SWITCHING DEVICE Robert E. Mumma, Dayton, Ohio,assignor to The National Cash Register Company, Dayton, Ohio, acorporation of Maryland Original application December 27, 1943, SerialNo. 515,718. Divided and this application July 19, 1947, Serial No.762,040

18 Claims. 1

This invention relates to an electron tube relay switching device forselectively routing electric signals.

This is a division of my co-pending application for United StatesLetters Patent, Serial No. 515,718, filed December 27, 1943, for aCalculating device, which issued on June 1, 1948, as Patent No.2,442,428.

The novel switching device disclosed herein provides a plurality ofgaseous discharge electron tubes arranged in an operative pattern ofrows, columns, and resultant diagonals. The terms columns, rows andresulting diagonals as used herein are not used to refer to the physicallocation of the tubes of the switching device but rather are used as ameans for setting forth the pattern of the network of connections bywhich the tubes are connected in various related groups to enable theselective routing of signals to be accomplished. These rows, columns,and diagonals utilize the same tubes, so that the pattern is overlaid,and thereby control potentials may be applied to a selected row of tubesand a selected column of tubes to actuate a selected tube so as to causeit to conduct and to send an electric signal out on a conductorconnecting all the tubes on its associated diagonal.

The invention is especially adapted for use in distributing impulse datato a denominational product accumulator of a multiplying device, such asthat shown in the aforementioned patent application, of which this is adivision, wherein product data is distributed to different denominationsof the product accumulator according to that particular digit ofmultiplier creating the product data which is then controlling. In suchuse of the device, each horizontal row of the electron tubes representsa particular multiplicand denomination, each column of tubes representsa particular multiplier denomination, and each diagonal output conductorrepresents a certain correlated denomination of the product accumulator.By an appropriate steady potential applied to the tubes of a selectedcolumn and by application of electric impulses applied to the tubes of aselected row, a certain one of the plurality of tubes is selected andcaused to become conducting once in response to each impulse and tothereby create a corresponding number of relayed impulses on itsassociated diagonal output conductor. Each tube is arranged in a circuitso as to become self-extinguished immediately after becoming conducting,so as to be ready to respond to another impulse.

The electron tube relays respond in a matter of micro-seconds, andconsequently the relaying of impulses may be accomplished very rapidly.

The electron tubes used are of the thyratron type having an anode, acathode, and a control electrode, all immersed in an ionizable gas.

For the particular purpose of this disclosure, as an example only, thecharacteristics of the tube disclosed are such that, with ananodecathode potential of approximately '70 volts, the tube will fireand become conducting when the control electrode becomes more positivethan about 12 volts negative with respect to the cathode and wherein theanode-cathode potential drop is about 15 volts during conduction.

From the foregoing, it will be understood that the principal object ofthe invention is to provide an electronic device for relaying androuting electric impulse data.

With this and incidental objects in view, the invention includes certainnovel features of construction, circuits, and combinations of parts, theessential elements of which are set forth in appended claims and apreferred form or embodiment of which is hereinafter described withreference to the drawings which accompany and form a part of thisspecification.

Of the drawings:

Fig. 1 shows a typical embodiment of the device having seven diagonaloutput channels.

Fig. 2 shows a denomination of an electron tube denominationalaccumulator of impulse data, showing the interrelation of suchaccumulator to the elements of Fig. 1 to provide for self-extinguishingof the tubes of Fig. 1 and to indicate how the relayed impulses may beutilized.

Values of potential, resistance, and capacitance, as given, are relativeand are given as one set of values which result in proper operation withthe specified tubes, but are not to be considered as limiting theinvention, as the principles involved permit of difierent values andrelations of values when other electron tubes are used. Potentials givenare with respect to ground potential.

GENERAL DESCRIPTION The tubes of the switching device are, as has beenstated, members in three overlaid groupings. One grouping relates totubes connected to the same diagonal output conductor. The secondgrouping relates to tubes having the same signal impulse conductor. Thethird grouping relates to tubes having the same grid priming conductor.In this showing, a signal impulse conductor joins tubes of a horizontalrow, and a priming conductor joins tubes of a vertical row.

In Fig. 1, the relay tubes are shown, and their grouping is as follows:

Diagonal grouping Signal impulse grouping (horizontal) Input TubesTerminal Priming grouping (vertical) Priming Tubes Terminal It is to beunderstood that the operational relation of the tubes is not dependenton the location of the tubes in space, as their coordinate relation isnot dependent on the juxtaposition of the tubes themselves as long asthey are connected by conductors in the pattern shown in Fig. l.

Seventy volts anode potential is supplied to each tube. There is aseparate potential source for the anodes of each diagonal row of tubes,and there is a 1,500-ohm resistor in series between each source and theanodes of its associated tubes. For instance, the source 1360 isconnected through resistor [8'10 to supply tube 1810 with anodepotential. The following table gives the other anode potential sourcesand the diagonal group of tubes supplied by each.

Potential Source Tubes The grid of a tube is connected conductively to asource of biasing potential and is also coupled electrostatically to thesignal impulse conductor of its associated row. Thus, for instance, thegrid of tube 1818 is connected to terminal 899, from which it receivesits bias potential, and is also coupled electrostatically to signalimpulse input terminal 108 by way of conductor i800 and capacitor 1650of .001 microfarad. All tubes in a column have the same bias potentialsource, and all the tubes in a row are coupled electrostatically to thesame signal impulse conductor.

The cathodes oi the tubes which are associated in a diagonal group areconnected to a common diagonal output conductor which is grounded 4through a resistor of 50,000 ohms, like resistor 1880 furnishing cathodepotential to tube 1810.

It will now be apparent that, to prevent the tubes of a column fromconducting, a controlling bias potential may be placed on the commonbias supply terminal for that column. When a column is to be primed,this bias potential is reduced to near the critical value, and then apositive potential impulse of small magnitude on a signal impulseconductor will cause the tube thereby selected to fire. When a tubefires, its cathode rises in potential due to the resistance in itscathode circuit. The output terminal for a diagonal row is coupled tothe cathodes of the tubes of the row through a capacitor, and, as anytube of the row fires, a positive impulse is impressed through saidcapacitor. Thus the capacitor between terminal 1650 and the cathode ofthe tube 1840 serves to couple all of the tubes of the associateddiagonal-namely, tubes 1840, 2190, 2110, and 2120-to said outputterminal 1650.

As this switching device is embodied in the multiplying device of myco-pendlng application to which reference has been made and of whichthis is a division, priming terminals 1890, 2150, and 2250 are given anormally controlling bias of 68 volts with reference to the cathodepotential, which is relieved to about 18 volts in the primed condition.Any one or all of the columns may be placed in primed condition byapplication of the proper potentials to the selected priming terminals.

It will be apparent that the magnitude of the signal impulses should besuch as to discriminate between a primed tube and an unprimed tube. Forthe values of potential given, positive signal impulses of from 20 to 40volts and of fairly steep wave front will give reliable operation.

As has been said, each time a tube fires, it is i. extinguishedimmediately due to circuit elements permitting a high initial surge ofcurrent through a fired tube followed by a sudden lowering of thecurrent. This results in an oscillatory rise in potential of the cathodeby reason of the distributed inductance of the wiring, causing atemporary cessation of anode-cathode potential and deionization of thetube, allowing the control element to resume its control.

In the disclosed embodiment of the invention, the elements contributingto cause the high initial current in a tube of Fig. 1 as it fires arethe capacitor joining any one of the diagonal output conductors to itsoutput terminal and the coupling of such output terminal to thecorresponding input terminal of a denominational bank of an electronicaccumulator, as is shown in Fig. 2. For instance, terminal 1630 (Fig. 1)is shown coupled to terminal 1630 (Fig. 2) and the input conductor ofthe counting ring shown therein. This input conductor is connectedcapacitatively to the grid bias negative potential source of each 01 thedigit-representing tubes of Fig. 2 numbered 0 to 9 inclusive. Thus, thediagonal output conductor joining the tubes 2100 and 1820 (Fig. 1) iscoupled to ground and to one side of a capacitor Whose other side isconnected to terminal 1630, which in turn is coupled capacitatively to asource of bias potential. Thus, as either tube 1820 or 2100 fires, thecapacitor coupling its cathode to terminal 1030 discharges through thetube, causing a high momentary current, which is suddenly reducedsharply by the presence of the cathode resistor as the capacitor isdischarged. The distributed inductance in the wiring causes the cathodesof tubes I820 and ZIUD to rise in a positive direction, momentarily, toa point more positive than the anode supply potential, thusextinguishing the tube that was conducting.

It will be understood that the particular embodiment of the inventionshown herein was taken from my co-pending application Serial No. 515,-718, wherein the coupling of a diagonal output conductor through acapacitor to an input conductor of a counting ring, which inputconductor itself is coupled to a source of potential, was merely the useof a convenient electrostatic power source to cause the temporary highcurrent in the firing tube. The same effect could be secured by couplingan output terminal, like terminal I630, directly to a source ofpotential.

As each output group of tubes is supplied separately with potential,adjustment may be made in the circuit constants of a particular group toadjust the output impulse strength. A means also is provided, as shownin Fig. 1, wherein point 2340 is connected through a resistor 2310 to asource of potential, for loading an output terminal for additionaladjustment of the output impulses. By the foregoing two means, theoutput signals from any diagonal output conductor may be adjusted to thedemands of the particular devices into which they are fed.

While the invention is shown in the specification and drawings in apreferred embodiment, the principle thereof is not confined to it but issusceptible of embodiment in various forms coming within the scope ofthe claims.

What is claimed is:

1. In a selective switching device, the combination of a plurality ofelectron tubes, each tube having at least an anode, a cathode, and meansto control conduction therein; a plurality of input conductors on whichinput signals may be impressed; means coupling the input conductors tothe control means of the tubes to form a plurality of input row groupsof said tubes, each row group containing one or more tubes; a pluralityof switching control circuits connecting the tubes of the row groupsinto control column groups of one or more tubes, any column group havingno more than one tube of any row group, said control circuits beingconnected to the control means of the tubes of their related columngroups and supplying the control means normally with a bias potentialwhich will prevent the input signals from causing conduction in thetubes, which potential can be modified selectively in any of the controlcircuits to relieve the bias and prime the tubes of the selected columngroup to respond to input signals; and further means con necting thetubes of the input row groups and control column groups into parallelgroups diagonal to the input row groups and to the control columngroups, said further means including a separate anode-cathode potentialsupply circuit for the tubes of each diagonal group, an output conductorfor each diagonal group and couplings between the tubes of a diagonalgroup and the output conductor to cause an output signal on the outputconductor whenever a tube in its related diagonal group conducts; saidinput conductors and their coupling to the tubes and said switchingcontrol circuits cooperating to control the conduction in the tubes toenable input signals on any predetermined set of input conductors tocause output signals to occur selectively on different sets of diagonalgroup output conductors.

2. In a selective switching device, the combination of a plurality ofgaseous discharge electron tubes, each tube having at least an anode, acathode, and means to control conduction therein; a plurality of inputconductors on which input signals may be impressed; means coupling theinput conductors to the control means of the tubes to form a pluralityof input row groups of said tubes, each row group containing one or moretubes; a plurality of switching control circuits connecting the tubes ofthe row groups into control column groups of one or more tubes, anycolumn group having no more than one tube of any row group, said controlcircuits being connected to the control means of the tubes of theirrelated column groups and supplying the control means normally with abias potential which will prevent the input signals from causingconduction in the tubes, which potential can be mod-ified selectively inany of the control circuits to relieve the bias and prime the tubes ofthe selected column group to respond to input signals; and further meansconnecting the tubes of the input row groups and control column groupsinto parallel groups diagonal to the input row groups and to the controlcolumn groups, said further means including a separate anode-cathodepotential supply circuit for the tubes of each diagonal group, saidanode-cathode potential supply circuits having values of resistance,capacitance and inductance which cause the tubes to be selfextinguishedafter having been rendered conducting, an output conductor for eachdiagonal group and couplings between the tubes of a diagonal group andthe output conductor to cause an output signal on the output conductorwhenever a tube in its related diagonal group conducts; said inputconductors and their coupling to the tubes and said switching controlcircuits cooperating to control the conduction in the tubes to enableinput signals on any predetermined set of input conductors to causeoutput signals to occur selectively on different sets of diagonal groupoutput conductors.

3. A plurality of electron tubes; and means connecting the tubes in asquare operative pattern of rows and columns having resultant parallelsdiagonal to the rows and columns, said means including a commonoperating energy supply for all the tubes on the same diagonal, a commoninput circuit for all the tubes in a row, and a common control circuitfor all the tubes in a column; said input circuits and control circuitscooperating to select the diagonals in which tubes will operate.

4. A plurality of gaseous electron tubes arranged in a square operativepattern of rows and columns having resultant parallels diagonal to therows and columns; a common operating energy supply for all the tubes onthe same diagonal; an output circuit related to each diagonal of thepattern; means coupling the output circuit to the tubes of the relateddiagonal to be energized each time one of the tubes of the relateddiagonal operates; a common input impulse circuit for all the tubes in arow; and a common control circuit for all the tubes in a column; saidinput circuits cooperating to control the operation of the tubes toselect which output circuits will be energized by input impulses on theinput circuits.

5. A plurality of electron tubes, each of said tubes having at least ananode, a cathode, and a control element; and means connecting the tubesin an operative switching network pattern of input rows, control columnsand resultant output parallels diagonal to the rows and columns, saidnetwork including an anode-cathode electric supply circuit common to thetubes of each output diagonal, an output conductor related to the tubesof each output diagonal, means coupling the output conductors to thetubes of their related diagonals to enable an output signal to beimpressed on an output conductor each time a tube in its relateddiagonal operates, a control element electric supply circuit common tothe tubes of each control column, and an input signal circuit common tothe control elements of the tubes of each input row, the input signalcircuits and control element electric supply circuits cooperating tocontrol the operation of the tubes to determine on which output circuitsoutput signals will be produced by input signals on the input signalcircuits, whereby input signals on a related group of input circuits cancause output signals to appear on a selected one or another relatedgroup of output conductors as controlled by the control element electricsupply circuits.

6. A plurality of gaseous electron tubes each tube having at least ananode, a cathode and a control element; and means connecting the tubesin a switching network having an operative pattern of a plurality ofinput rows, a plurality of control columns, and a plurality of outputparallels diagonal to the rows and columns, the

network including an anode-cathode electric supply circuit common to thetubes of each diagonal, an output circuit for each output diagonal,means coupling the output circuits to the oathodes of the tubes of theirrelated diagonal to receive an output impulse when any tube of thediagonal conducts, a control element electric supply circuit common tothe tubes of each control column, and a signal input impulse circuit.coupled to the control elements of the tubes of each input row, thesignal input circuits and the control element electric supply circuitscooperating to control conduction in the tubes to determine on whichoutput circuits output impulses will be produced as a consequence ofinput impulses on input circuits, the controls enabling input impulseson a related group of input circuits to cause output impulses to appearselectively on one or other related groups of output circuits asdetermined by the control exerted by the control element electric supplycircuits.

'7. A plurality of electron tubes each having at least an anode, acathode, and a control element; means connecting the tubes in columngroups, said means including a separate common control element electricsupply circuit common to all the tubes in a column group for supplyingnormal disabling bias to the tubes of the group, which bias if reducedin a circuit primes the tubes of the column group for operation; meansconnecting the tubes of the column groups in row groups squared to thecolumn groups so that a row group will have but one tube from a givencolumn group, said means including a separate input signal circuitcommon to all the tubes in a row group, signals on said signal inputcircuits being effective to cause the operation only of primed tubes;and means connecting the tubes of row groups and column groups inparallel groups diagonal to the row and column groups, said meansincluding a separate anode-cathode electric supply circuit common to allthe tubes in a diagonal group.

8. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential biascircuit common to all the control elements of the tubes of a columngroup, said circuits each being normally furnished with suflicientpotential to prevent conduction in any associated tube which bias may berelieved selectively to prime tubes of any column group; meansconnecting the tubes of the column groups in row groups squared to thecolumn groups so that a row group will have but one tube from a givencolumn group, said connecting means including a separate input conductorelectrostatically connected to each of the control elements of the tubesof a row group; and means further connecting the tubes of the row groupsand the column groups in parallel groups diagonal to the row and columngroups, no diagonal group having more than one tube in any row or columngroup, said further connecting means including an anode-cathode electricsupply circuit common to the tubes of a diagonal group.

9. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode,

and a control element; means connecting the tubes in column groups, saidmeans including an electric potential bias circuit for each column groupand connected to all the control elements of the tubes of the relatedcolumn group, said circuits each being normally furnished withsufiicient potential bias to prevent conduction in any associated tubein response to input signals which bias is relieved selectively to primethe tube of any column group to enable them to respond to input signals;means connecting the tubes of the column groups in row groups squared tothe column groups so that a row group will have but one tube from agiven column group, said connecting means including a separate inputconductor coupled to the control elements of the tubes of a row forimpressing input signals on the tubes; and means further connecting thetubes of the row groups and the column groups in parallel groupsdiagonal to the row and column groups, no diagonal group having morethan one tube in any row or column group, said further connecting meansincluding an anode-cathode electric supply circuit common to the tubesof a diagonal group.

10. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential biascircuit common to all the control elements of the tubes of a columngroup, said circuits each being normally furnished with sufficientpotential to prevent conduction in any associated tube in response toinput signals, which potential can be modified selectively on the biascircuits to reduce the bias and prime the tubes of the selected columngroup to enable them to respond to input signals; means connecting thetubes of the column groups in row groups squared to the column groups sothat a row group will have but one tube from a given column group, saidconnecting means including a separate input conductor electrostaticallyconnected to each of the control elements of the tubes of a row groupfor applying input signals thereon; and means connecting the tubes ofthe row groups and column groups in parallel groups diagonal to the rowand column groups, no diagonal group having more than one tube in anyrow or column group, said connecting means including an anodecathodeelectric supply circuit common to the 1 .9 tubes of a diagonal group,said supply circuits having values of resistance, capacitance, andinductance which cause a tube in the circuit to be self-extinguishedwhen rendered conducting.

11. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential biascircuit common to the control elements of all the tubes of a column,each of said circuits being connected to the control elements of thetubes of a related column group and normally furnishing the controlelements of the column group with sufficient potential to preventconduction in any associated tube in response to input signals, whichpotential if modified on the circuits selectively will relieve the biasand allow the tubes of a selected column group to respond to inputsignals; means connecting the tubes of said column groups in row groupssquared to the column groups so that a row group will have but one tubefrom a given column group, said connecting means including a commoninput conductor electrostatically connected to the control elements ofth tubes of a row group to impress input signals thereon; meansconnecting the tubes of the row and column groups in parallel groupsdiagonal to the row and column groups, no diagonal group having morethan one tube in any row or column group, said connecting meansincluding an anode-cathode electric supply circuit common to the tubesof each diagonal group; and means to prepare the tubes of a column tofire by relieving the controlling bias potential to near the criticalpoint.

12.A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential biascircuit related to each column group and connected to all the controlelements of the tubes of its related column group, said circuits eachbeing normally furnished with sufi'icient potential to preventconduction in any associated tube which potential can be modifiedselectively on the bias circuits to reduce the bias and prime the tubesof the selected column; means connecting the tubes in row groups squaredto the column groups so that a row group will have but I) one tube froma given column group, said connecting means including a common inputconductor electrostatically connected to the control elements of thetubes of a row group and upon which signals are impressed which areineffective on unprimed tubes; means connecting the tubes in parallelgroups diagonal to the row and column groups, no diagonal group havingmore than one tube in any row or column group, said connecting meansincluding an anode-cathode electric supply circuit common to the'tubesof a diagonal group; said input conductors and bias circuits cooperatingto control the selective operation of the tubes to govern in whichdiagonal group a tube will operate when a signal is impressed on theinput conductors; a plurality of output means; and means coupling anoutput means tothetubes of a diagonal group to enable an output signalto be impressed on the output means each time a tube of its relateddiagonal group operates.

13, A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential biascircuit connected to all the control elements of the tubes of a columngroup,

i said circuits each being normally furnished with suflicient potentialto prevent conduction in any associated tube, said potential whenmodified on any selected circuit enabling the tubes oi'that column groupto conduct in response to input signals; means connecting the tubes ofthe column groups in row groups squared to the column groups so that arow group will have but one tube from a given column group, saidconnecting 'means impressing input signals on the tubes of the rowgroups and including a common input conductor electrostaticallyconnected to the control elements of the tubes of a row group; meansfurther connecting said tubes in parallel groups diagonal to the row andcolumn groups, no diagonal group having more than one tube in any row orcolumn group, said further connecting means including an anode-cathodeelectric supply circuit common to the tubes of a diagonal group; andmeans to cause a selected tube to conduct by relieving the bias on thecolumn group in which the tube is located and simultaneously impressinga positive impulse on the input conductor for the row group in which thetube is located.

14. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting thetubes'in column groups, said means including an electric potential biassource circuit common to all the control elements of the tubes of acolumn group, said circuits each being normally furnished withsuflicient potential to prevent conduction in any associated tube which'potential can'be selectively modifiedto allow tubes of any selectedcolumn group to respond to input signals; means connecting the tubes ofthe column groups in row groups squared to the column groups so that arow group will have but one tube from a given column group, saidconnecting means impressing input signals on related row groups andincluding a separate input conductor electrostatically connected to thecontrol elements of the tubes of a row group; and means connecting saidtubes in parallel groups diagonal to the row and column groups, nodiagonal group having more than one tube in any row or column group,said connecting means including an anode-cathode circuit common to thetubes of a diagonal group, said circuit including a common cathodepotential supply source and a resistance in parallel with a capacitorconnecting said source with said cathodes.

15. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential bias sourcecircuit for each column group and connected to all-the control elements,of the tubes of a related column group, said circuits each beingnormally furnished with sufficient potential to prevent conduction inany associated tube in response to inputsignals, which bias may berelieved selectively on anycircuit to enable the tubes of the relatedcolumn group to respond to input signals; meansconnecting'the tubes inrow groups squared to the column groups so that a row group will havebut one tube from a given column group, said connecting means enablinginput signals to be impressed on the row groups and including a separateinput conductor for each row group which is electrostatically connectedto the control elements of the 1! tubes in a related row group; andmeans connecting the tubes in parallel groups diagonal to the row andcolumn groups, no diagonal group having more than one tube in any row orcolumn group, said connecting means including an anod cathode circuitcommon to the tubes of a diagonal group, said circuit including a commoncathode potential supply source and a resistance in parallel with acapacitor connecting said source with said cathodes, the values ofresistance and 1.

capacitance in combination with normal distributed wiring inductancecausing any conducting tube to become extinguished by cessationmomentarily anode-cathode potential.

16. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential bias sourcecircuit for each column group and connected to the control elements ofall the tubes of its related column group, said circuits each beingnormally furnished with sufllcient potential to prevent conduction inany associated tube in response to input signals, which bias may berelieved selectively on any circuit to enable th tubes of the relatedcolumn group to respond to input signals; means connecting the tubes inrow groups squared to the column groups so that a row group will havebut one tube from a given column group, said connecting means includinga separate input conductor electrostatically connected to th controlelements of the tubes of a row group to impress input signals thereon;means connecting the tubes in parallel groups diagonal to the row andcolumn groups, no diagonal group having more than one tube in any row orcolumn group, said connecting means including an anode-cathode circuitcommon to the tubes of a diagonal group, the cathode portion of saidcircuit including a common cathode potential supply source and aresistance in parallel with a capacitor connecting said source with saidcathodes, the values of resistance and capacitance in combination withnormal distributed wiring inductance causing any conducting tube tobecome extinguished; and an output circuit connected to the cathodes ofthe tubes or a diagonal group, which output circuit is given a potentialimpulse as any associated tube commences to conduct.

17. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential bias sourcecircuit common to all the tubes of a column group, said circuits eachbeing normally furnished with sufiicient potential to prevent conductionin any associated tube: means connecting the tubes in row groups squaredto the column groups so that a row group will have but one tube from agiven column group, said connecting means including a separate inputconductor electrostatically connected to the control elements of thetubes of a row group; means connecting the tubes in parallel groupsdiagonal to the row and column groups, no diagonal group having morethan one tube in any row or column group, said connecting meansincluding an anodecathode circuit common to the tubes of a diagonalgroup, the cathode portion of said circuit including a common cathodesupply source and a resistance in parallel with a capacitor connectingsaid source with said cathodes, the values of resistance and capacitancein combination with normal distributed wiring inductance causing anyconducting tube to become extinguished; an output circuit connected tothe cathodes of the tubes of a diagonal group, which output circuit isgiven a potential impulse as any associated tube commences to conduct;and means to relieve the normal bias potential on the tubes of anycolumn group to near the critical point where a tube in the column groupmay b fired to the exclusion of any other tube by impressing a potentialim pulse on its input conductor suincient to overcome the relieved biasbut insufiicient to fire other normally biased tubes of the row group.

18. A plurality of gaseous discharge electron tubes each having at leastan anode, a cathode, and a control element; means connecting the tubesin column groups, said means including an electric potential bias sourccircuit common to all the tubes of a column group, said circuits eachbeing normally furnished with suflicient potential to prevent conductionin any associated tube: means connecting the tubes in row groups squaredto the column groups so that a row group will have but one tube from agiven column group, said connecting means including a separate inputconductor electrostatically connected to the control elements of thetubes of a row group; means connecting the tubes in parallel groupsdiagonal t0 the row and column groups, no diagonal group having morethan one tube in any row or column group, said connecting meansincluding an anodecathode circuit common to the tubes of a diagonalgroup, the cathode portion of said circuit including a common cathodesupply source and a resistance in parallel with a capacitor connectingsaid source with said cathodes, the values of resistance and capacitancein combination with normal distributed wiring inductance causing anyconducting tube to become extinguished; an output circuit connected tothe cathodes of the tubes of a diagonal group, which output circuit isgiven a potential impulse as any associated tube commences to conduct;means to relieve the normal bias potential on the tubes of any selectedcolumn group toward the critical firing point; and means to impress apositive potential impulse on any input conductor sufficient to fire atube in the row group having its bias potential relieved, whereby anyselected tube of the plurality may be rendered momentarily conducting tofurnish an electric impulse to its associated output circuit.

ROBERT E. MUMMA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,402,989 Dickinson July 2, 19462,404,697 Desch et al July 23, 1946 2,408,086 Meacham et al. Sept. 24,1946

